Machine and Method for Additive Manufacturing

Abstract

An additive manufacturing machine is offered which creates a three-dimensional (3D) object by melting a powdered material with a beam such an electron beam and which shapes the surface of the 3D object at improved accuracy. The 3D object is obtained by tightly spreading the powdered material ( 31 ) on a support stage ( 43 ) and illuminating the powdered material ( 31 ) with a beam (B) to melt and bond together grains of the powdered material. The beam generated by a beam generator ( 11 ) is a pulsed beam and used to melt or sublimate the powdered material.

The invention claimed is: 
     
         1 . An additive manufacturing machine comprising:
 a support stage on which a powdered material is spread tightly;   a beam generator producing a beam;   a lens for focusing the beam produced by the beam generator onto the powdered material spread on the support stage; and   a controller for causing the beam generator to selectively produce a continuous beam or a pulsed beam as the beam produced by the beam generator.   
     
     
         2 . The additive manufacturing machine as set forth in  claim 1 , wherein said controller melts said powdered material by illuminating the powdered material with said continuous beam and sublimates the powdered material by illuminating the powdered material with said pulsed beam. 
     
     
         3 . The additive manufacturing machine as set forth in  claim 2 , wherein said controller controls said lens such that a diameter of the beam used when the powdered material is sublimated is smaller than a diameter of the beam used when the powdered material is molten. 
     
     
         4 . The additive manufacturing machine as set forth in  claim 1 , wherein said beam generator is an electron gun producing an electron beam, and wherein the electron gun selectively produces a continuous electron beam and a pulsed electron beam under control of said controller. 
     
     
         5 . An additive manufacturing machine comprising:
 a support stage on which a powdered material is spread tightly;   an electron gun producing an electron beam;   a lens for focusing the electron beam produced by the electron gun onto the powdered material spread on the support stage; and   a controller for causing the electron gun to produce a pulsed electron beam as the electron beam produced by the electron gun.   
     
     
         6 . The additive manufacturing machine as set forth in  claim 5 , wherein said controller melts or sublimates the powdered material by illuminating the powdered material with said pulsed electron beam. 
     
     
         7 . The additive manufacturing machine as set forth in  claim 6 , wherein said controller supplies a drive voltage to said electron gun, the drive voltage being produced by superimposing a pulsed voltage on an offset voltage for heating the electron gun. 
     
     
         8 . The additive manufacturing machine as set forth in  claim 7 , wherein each pulse of said pulsed electron beam has a duration shorter than 1 microsecond. 
     
     
         9 . A method of fabricating a three-dimensional multilayered object by spreading a powdered material tightly on a support stage, illuminating the powdered material with a beam, and melting and bonding together grains of the powdered material to obtain the three-dimensional object, said method comprising the step of:
 selectively producing a continuous beam or a pulsed beam as the illuminating beam.   
     
     
         10 . A method of fabricating a three-dimensional multilayered object by spreading a powdered material tightly on a support stage and illuminating the powdered material with an electron beam from an electron gun to melt and cure the powdered material, said method comprising the step of:
 producing a pulsed beam as the electron beam produced by the electron gun to melt or sublimate the powdered material.